Absorption of Sub-MeV Fermionic Dark Matter by Electron Targets

TL;DR

This paper explores how sub-MeV fermionic dark matter can be detected through absorption by electrons in detectors, providing calculations and models to enhance detection prospects in current and future experiments.

Contribution

It introduces a new detection channel for sub-MeV fermionic dark matter via electron absorption, with detailed rate calculations and model proposals.

Findings

Fermionic absorption signals are sensitive to sub-MeV dark matter.

Calculated energy spectra for xenon detectors.

Projections show promising detection prospects.

Abstract

We study a new class of signals where fermionic dark matter is absorbed by bound electron targets. Fermionic absorption signals in direct detection and neutrino experiments are sensitive to dark matter with sub-MeV mass, probing a region of parameter space in which dark matter is otherwise challenging to detect. We calculate the rate and energy deposition spectrum in xenon-based detectors, making projections for current and future experiments. We present two possible models that display fermionic absorption by electrons and study the detection prospects in light of other constraints.